The invention relates to a seating furniture item, in particular an office chair, with a seat fastened to a seat support and with a backrest fastened to a backrest support, in which the backrest support is articulatedly arranged on a base support and the backrest support and the seat support are connected articulatedly with each other via two levers.
Such a seating furniture item is already known from the German Utility Model DE 20 2005 010 952 U1. It is distinguished by the possibility of a synchronous adjustment of the backrest and the seat, in which no relative movement occurs between the backrest and the clothing of a person who is seated. In addition, the lower part of the person's back remains well supported in all inclination positions of the backrest.
However, in the known seating furniture item a third lever is provided, which is mounted swivellably on the base support and positively guides the rear of the two levers which connect the seat support and the backrest support with each other. The known construction of the synchronous mechanism between the backrest and the seat is relatively complex due to the third lever which is required.